package com.stu.thread.file;

/**
 * @projectName: learn_used_code
 * @packageName: com.test.stream.utils
 * @className: com.test.stream.utils-> DecodeUtils
 * @createDate: 2022-01-06 11:00
 * @author: ZhangSheng
 * @version: 1.0
 * @description:
 */
public class DecodeUtils {

    //public static void main(String[] args) {
    //    String unicode = "zhong gongoaf 我是中国国人  \\u83b7\\u53d6\\u865a\\u673a\\u5931\\u8d25\\uff1a{}";
    //    String unicode2 = "我是中国国人 VmServiceImpl.log.error(\"\\u83b7\\u53d6\\u865a\\u673a\\u5931\\u8d25\\uff1a{}\", (Object)e.getLocalizedMessage());";
    //    System.out.println(DecodeUtils.decodeUnicode(unicode2));
    //}

    /**
     * unicode 转换成 中文
     * @param str
     * @return
     */
    public static String decodeUnicode(String str) {
        char aChar;
        int len = str.length();
        StringBuffer outBuffer = new StringBuffer(len);
        for (int x = 0; x < len;) {
            aChar = str.charAt(x++);
            if (aChar == '\\') {
                aChar = str.charAt(x++);
                if (aChar == 'u') {
                    // Read the xxxx
                    int value = 0;
                    for (int i = 0; i < 4; i++) {
                        aChar = str.charAt(x++);
                        switch (aChar) {
                            case '0':
                            case '1':
                            case '2':
                            case '3':
                            case '4':
                            case '5':
                            case '6':
                            case '7':
                            case '8':
                            case '9':
                                value = (value << 4) + aChar - '0';
                                break;
                            case 'a':
                            case 'b':
                            case 'c':
                            case 'd':
                            case 'e':
                            case 'f':
                                value = (value << 4) + 10 + aChar - 'a';
                                break;
                            case 'A':
                            case 'B':
                            case 'C':
                            case 'D':
                            case 'E':
                            case 'F':
                                value = (value << 4) + 10 + aChar - 'A';
                                break;
                            default:
                                throw new IllegalArgumentException("Malformed   \\uxxxx   encoding.");
                        }
                    }
                    outBuffer.append((char) value);
                } else {
                    if (aChar == 't')
                        aChar = '\t';
                    else if (aChar == 'r')
                        aChar = '\r';
                    else if (aChar == 'n')
                        aChar = '\n';
                    else if (aChar == 'f')
                        aChar = '\f';
                    outBuffer.append(aChar);
                }
            } else {
                outBuffer.append(aChar);
            }
        }
        return outBuffer.toString();
    }
}
